Several systems for releasing fragrant compounds have been described in the prior art. Firmenich PCT publication WO 99/60990 describes a fragrance delivery system that releases fragrant alcohols, aldehydes or ketones upon exposure to light. The system of that publication comprises 2-benzoyl benzoates or α-keto esters which are used as fragrance precursors.
There exists, in perfumery, a particular interest in compounds which are capable of “fixing” fragrant molecules, for example by chemical bonding or intramolecular forces like adsorption, and releasing these fragrant molecules over a prolonged period of time, for example by the action of heat, enzymes, or even sunlight (fragrant molecules have to be volatile in order to be perceived). Although many known fragrant compounds show a good substantivity, i.e., they will remain on a surface to which they have been applied for several days and can hence be perceived over such a period of time, a great number of fragrant compounds are very volatile, and their characteristic odor can no longer be perceived several hours after their application.
It is thus desirable to dispose of fragrance delivery systems which are capable of releasing the fragrant compound or compounds in a controlled manner, maintaining a desired scent over a prolonged period of time.
Therefore, in view of their importance in the field of perfumery, systems allowing the slow release of fragrant compounds constitute an object of intensive research in order to find new precursors capable of releasing different odorous compounds.
Phenyl ketones are known to be photolabile molecules. In fact, the photochemistry of these compounds was extensively studied in the prior art. One can cite for instance P. J. Wagner, in Acc. Chem. Res., 1971, 4, 168-171, or in Top. Curr. Chem. 1976, 66, 1-52.
Moreover, W. W. Epstein et al. disclose in Anal. Biochem. 1982, 119, 304-312 the use of alkyl phenyl ketones as photolabile linkage inserted in a detergent in order to cleave the latter under photolysis and to form a water-soluble compound and an olefin.
However, the prior art does not disclose the use of phenyl ketones as precursors of fragrant compounds, masking agents, antimicrobial agents or other active compounds or as being part of perfuming, masking, antimicrobial, insect repelling or insect attracting compositions or products, the latter providing systems that are capable of slowly releasing the active compounds. This is the discovery of the present inventors.